Is there a way to automatically un-tab everything in your source file by using a command? [closed]

Question

And then to automatically re-indent after that? I've tried copying code from one terminal screen to the other, but the tabulation got all messed up.

I didn't know what to call this functionality, so it was hard for me to find it on google (which generally returned things related to how to set tab size, which wasn't what I was looking for unfortunately).

Answer 1

Vim has a retab command that allows you to tabify or untabify your document. It uses settings such as tabstop and expandtab. So, if you want to replace tabs with spaces you could do the following:

:%retab

See the retab documentation for full details.

Caveat Emptor: this also replaces tabs that are NOT at the beginning of a line. So if you use hard tabs in the middle of strings they will be replaced as well.

Answer 2

To expand on @Kaleb's answer (I don't have the rep yet to comment), before executing the retab command, you will need to :set expandtab (set et). Otherwise the retab will not replace tabs with spaces.

In additon, you may wish to specify the tabstops. Often in source code created by others, the code is written with tabstops set to 4 or even 2. Before doing the :%retab command, experiment with different tabstops. Try

:set ts=8 (the default)
:set ts=4 
:set ts=2  

to see which setting makes the most sense.

To go backwards (replacing spaces with appropriate TAB characters, use

:set noet
:%retab!

Answer 3

By un-tab, do you mean to change tabs to spaces? If so, substitute spaces for tabs in the entire buffer like this:

:%s/^I/    /g

That's four spaces on the right side of the substitution, but you can make it whatever number you want. To get the literal ^I tab character, you can hit ^V followed by the Tab key.

You can re-indent with the = command. To re-indent the entire contents of the buffer, use these commands:

gg
=G

This takes you to the top, then re-indents everything to the bottom.